CWE-295 证书验证不恰当

Improper Certificate Validation

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: unkown

基本描述

The software does not validate, or incorrectly validates, a certificate.

扩展描述

When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1003 cwe_Ordinal: Primary

• cwe_Nature: PeerOf cwe_CWE_ID: 322 cwe_View_ID: 1000

适用平台

Language: {'cwe_Class': 'Language-Independent', 'cwe_Prevalence': 'Undetermined'}

Paradigm: {'cwe_Name': 'Mobile', 'cwe_Prevalence': 'Undetermined'}

常见的影响

检测方法

Automated Static Analysis - Binary or Bytecode

Manual Static Analysis - Binary or Bytecode

Dynamic Analysis with Automated Results Interpretation

Dynamic Analysis with Manual Results Interpretation

Manual Static Analysis - Source Code

Automated Static Analysis - Source Code

Architecture or Design Review

可能的缓解方案

['Architecture and Design', 'Implementation']

策略:

Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.

Implementation

策略:

If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.

示例代码

例

This code checks the certificate of a connected peer.

bad C

In this case, because the certificate is self-signed, there was no external authority that could prove the identity of the host. The program could be communicating with a different system that is spoofing the host, e.g. by poisoning the DNS cache or conducting a man-in-the-middle attack.

例

The following OpenSSL code obtains a certificate and verifies it.

bad C

Even though the "verify" step returns X509_V_OK, this step does not include checking the Common Name against the name of the host. That is, there is no guarantee that the certificate is for the desired host. The SSL connection could have been established with a malicious host that provided a valid certificate.

例

The following OpenSSL code ensures that there is a certificate and allows the use of expired certificates.

bad C

If the call to SSL_get_verify_result() returns X509_V_ERR_CERT_HAS_EXPIRED, this means that the certificate has expired. As time goes on, there is an increasing chance for attackers to compromise the certificate.

例

The following OpenSSL code ensures that there is a certificate before continuing execution.

bad C

Because this code does not use SSL_get_verify_results() to check the certificate, it could accept certificates that have been revoked (X509_V_ERR_CERT_REVOKED). The software could be communicating with a malicious host.

例

The following OpenSSL code ensures that the host has a certificate.

bad C

Note that the code does not call SSL_get_verify_result(ssl), which effectively disables the validation step that checks the certificate.

分析过的案例

分类映射

相关攻击模式

• CAPEC-459

引用

• REF-243 Why Eve and Mallory Love Android: An Analysis of Android SSL (In)Security

• REF-244 Computer Security: Art and Science

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